I agree with halfprice, Ford is warrantying the suspension, not Thor and I doubt that Ford will deny a warranty claim based on industry standard suspension modifications.
Having said that, make sure before you do anything, that the suspension is ok. Look at the thread
https://www.thorforums.com/forums/f2...des-24306.html, not that Ford will do anything about a nose down attitude. Them is just the breaks. Get it aligned, correctly.
David